1. Field of the Invention
Embodiments relate to an additive composition and a positive polishing slurry composition including the additive composition.
2. Description of the Related Art
Chemical mechanical polishing (CMP) is one of semiconductor processing technologies of performing mechanical processing by an abrasive between a pressurized wafer and a polishing pad while performing chemical etching by chemical components of a slurry, and is used as an essential process of a widespread planarization technology in manufacturing of a semiconductor chip of a submicron scale. A slurry composition for oxides among slurry compositions may be used to polish an interlayer dielectric and a silicon oxide layer used for a shallow trench isolation (STI) process. A ceria slurry composition including ceria as abrasive particles is widely used to polish a silicon oxide layer in the STI process, and a silicon nitride layer is mainly used as a polishing stop layer. Generally, to increase a polishing selectivity of an oxide layer to a nitride layer, a predetermined chemical additive composition may be added to the ceria slurry composition. An additive composition may have a selectivity and a planarization degree based on a carboxylic group-containing polymer, and may be optimized for a negative slurry composition having negative charges. When the additive composition is used in a positive slurry composition having positive charges, a polishing rate, a selectivity and a planarization degree may decrease due to aggregation and reaction with the slurry composition. A positive slurry may realize a high polishing rate with a high reaction with a wafer and a pad, however, may be vulnerable to the selectivity and the planarization degree. Thus, there is a desire for development of an additive composition to increase a selectivity and a planarization degree while maintaining a high polishing rate when the additive composition is used together with a positive slurry composition.